What are the principles of the unjust factor in determining special costs?

In Just v. British Columbia, [1992] B.C.J. No. 1370, Donald J. (as he then was) stated at p. 6: The principles relating to the unjust factor appear to be these: (1)where ordinary costs fail to meet one-half special costs an injustice presumptively arises because ordinary costs are designed to achieve that result; (2)the conduct of the parties may justify increased costs in a negative sense by the use of hard nosed and burdensome tactics or in a positive sense by the application of industry and cooperation that reduces the number and duration of pre-trial procedures and shortens the trial; and, (3)the unusual nature of the case or its difficulty or importance may be such that the structure of the tariff simply cannot produce fair indemnity and more than 50% of special costs must be awarded to do justice.